Do they require annual DSCR tests?

Cash up front would be a bigger requirement for STRs too so it's not a "cash-flow" method, it's just your moving cash around differently.

I am an experienced renovator, having done work and management on all aspects of my own properties from the foundation up for 18 years.Since the State laws are new, I'm excited about the possibilities, and looking to chat with other Owner/Builders about the feasibility and pitfalls.I guess that my biggest open questions are about foundations and waste water management requirements in conjunction with an existing multi family building. 

As per the article from CAS below, it does require disclosure.

It might mean you can consider slightly higher purchase prices or invest in properties that require more rehab.

Buyers: How do you feel about the requirement for written agreements before seeing homes?

I calculate that a quadplex would make my effective rent $350 below what I'm paying in rent today and when its fully rented it would bring in $700.It takes longer to get the quad but it has a positive effect on my saving rate versus treading water in the duplex which requires me to move to "make" money.

I earn much higher returns than I ever did as a rental investor, with almost no work required on my part.

Does the down payment and income requirements make it difficult for first time or low income buyers?   

These lines of credit generally have 1-2 year renewal periods and require you to send the bank your tax returns and possibly personal financial statement on an annual basis.In my experience "HELOCs" are associated with your primary residence.